1. Field of the Invention
The invention relates to a display and a weighted dot rendering method.
2. Description of the Related Art
In known display of the kind used in video, film and computer technology, so-called pixels are arranged along horizontally and/or vertically extending lines. The pixels generally consist of so-called dots representing the three basic colours red, green and blue. Dots are sources of luminous radiation the light of which is mixed to generate luminous mixed colours in a process referred to as additive mixing.
In computer monitors and television receivers the display is divided into a plurality of pixels arranged on a fixed grid or raster. Each pixel is controlled individually, with the pixels addressed from left to right and from the top to the bottom, for instance, as is customary practice for CRT screens.
EP 0 637 009 A2 discloses a method of controlling active LCD displays in which the dots are arranged in a mutually offset pattern to form a delta shape, with the dots of each colour group vertically interconnected by a control line. Horizontal control is effected pixelwise, meaning that the three dots of each RGB pixel are addressed at the same time. Further, each dot comprises a memory element and a switching element, whereby RGB data can be transmitted using synchronizing information, as is the case in conventional monitors, for example.
DE 36 06 404 A1 discloses a method of generating picture elements on a colour display, as well as a colour display. The method uses a light gate array of which the light gates are addressable individually by means of control circuitry in such a manner that the desired colour intensity is obtained by controlling the transmission properties of the respective light gate. Light sources are disposed behind the light gate to provide at least two primary colours and are switched in alternating light cycles at a repetition rate of at least 25 Hz, with the light gates being controlled synchronously therewith. Because of the inertia of the human eye, it is possible for a gate to display the desired colour.
One drawback of this kind of display is that the number of pixels is limited by the fixed grid, which limits the resolution and the picture sharpness as well. The finer the grid, the higher the resolution. The fineness of the grid itself is limited by manufacturing technology, however, because the cathode ray tubes that are used for the displays comprise so-called shadow masks having holes therein which cannot be reduced to whatever size unless one puts up with considerable expenditures.
U.S. Pat. No. 6,252,613 discloses a pixel addressing method using at least 2 scanning lines to address a pixel. This method increases the vertical spatial frequency comparing with conventional RGB stripe display and it does increase the overall resolution by a factor 1.5. The drawback is that it still applies rigid pixel addressing method which limits the display further to improve its both horizontal and vertical resolution.
Likewise, in LCD displays, the integration of a great number of thin film transistors (TFT) is extremely expensive and very prone to produce major amounts of rejects. In Plasma (PDP) or in FED displays, the technical and economical manufactured size of a RGB pixel is physically limited by the mass production technology itself and further reduction of the RGB pixel size for higher resolution cannot be achieved without huge manufacturing equipment cost and over proportional scraps which are economically not viable.
In LED displays, the placement of the LEDs is complicated and expensive as their space demand is predetermined by their shape.
The concept of using overlapping pixels by sharing dots with neighboring pixels to create a perceived higher resolution was disclosed in the U.S. Pat. No. 6,661,429, entitled “Dynamic Pixel Resolution for Displays Using Spatial Elements”. In the U.S. patent Publication No. 2003/0218618, which is a continuation-in-part of the U.S. Pat. No. 6,661,429, and entitled “Dynamic Pixel Resolution, Brightness and Contrast for Displays Using Spatial Elements,” this method was further elaborated to use time sequential overlapping of frames to reach a perceived higher resolution by the human vision. In the U.S. patent Publication No. 2004/0150651, which is a continuation-in-part of the U.S. patent Publication No. 2003/0218618, and entitled “Dynamic Pixel Resolution, Brightness and Contrast for Displays Using Spatial Elements,” weighted dot rendering method was applied to replace the time sequential method for reaching the same overlapping pixels effects.